Essential spectra of some matrix operators and application to two-group transport operators with general boundary conditions

In this article we investigate the essential spectra of a 2 × 2 block operator matrix on a Banach space. Furthermore, we apply the obtained results to determine the essential spectra of two-group transport operators with general boundary conditions in the Banach space Lp([−a, a]×[−1, 1])×Lp([−a, a]×[−1, 1]), a >0. © 2005 Elsevier Inc. All rights reserved